Finalising the PeerManager

cbf-staging

This is a work in progress staging area for a rust based BIP157 implementation, that is intended to be used as a backend for BDK based wallets.

The code is early draft.

Checkout current Issue Tracker and the Planning doc for better understanding of approach and current status.

	pub fn sync_headers<F>(
	peer: Arc<Peer>,
	store: Arc<ChainStore<Full>>,
	sync_fn: F,
	) -> Result<Option<ChainStore<Snapshot>>, CompactFiltersError>
	where
	F: Fn(usize) -> Result<(), CompactFiltersError>,
	{
	let locators = store.get_locators()?;
	let locators_vec = locators.iter().map(\|(hash, _)\| hash).cloned().collect();
	let locators_map: HashMap<_, _> = locators.into_iter().collect();

	peer.send(NetworkMessage::GetHeaders(GetHeadersMessage::new(
	locators_vec,
	Default::default(),
	)))?;
	let (mut snapshot, mut last_hash) = if let NetworkMessage::Headers(headers) = peer
	.recv("headers", Some(Duration::from_secs(TIMEOUT_SECS)))?
	.ok_or(CompactFiltersError::Timeout)?
	{
	if headers.is_empty() {
	return Ok(None);
	}

	match locators_map.get(&headers[0].prev_blockhash) {
	None => return Err(CompactFiltersError::InvalidHeaders),
	Some(from) => (store.start_snapshot(*from)?, headers[0].prev_blockhash),
	}
	} else {
	return Err(CompactFiltersError::InvalidResponse);
	};

	let mut sync_height = store.get_height()?;
	while sync_height < peer.get_version().start_height as usize {
	peer.send(NetworkMessage::GetHeaders(GetHeadersMessage::new(
	vec![last_hash],
	Default::default(),
	)))?;
	if let NetworkMessage::Headers(headers) = peer
	.recv("headers", Some(Duration::from_secs(TIMEOUT_SECS)))?
	.ok_or(CompactFiltersError::Timeout)?
	{
	let batch_len = headers.len();
	last_hash = snapshot.apply(sync_height, headers)?;

	sync_height += batch_len;
	sync_fn(sync_height)?;
	} else {
	return Err(CompactFiltersError::InvalidResponse);
	}
	}

	Ok(Some(snapshot))
	}